The present invention relates to a method and apparatus for controlling the brake pressure of the wheels of a brake circuit of a brake control system using measured and estimated values.
German published application DE-A1 4,030,724 discloses a system for controlling the dynamics of vehicle movement, including an ABS (antilock brake system) in which, based on measured and estimated values including the brake cylinder pressures, desired brake pressures are determined for the wheel brake cylinders, activation times for the vehicle hydraulic system including inlet valves are determined from the desired brake circuit pressures using an inverse hydraulic model, and the actual brake cylinder pressure is estimated from the brake circuit pressure and the activation times of the inlet and outlet valves associated with the individual brakes using a hydraulic model.
In this reference, the braking pressure in the wheel brake cylinder is estimated from the measured inlet pressure (=brake circuit pressure) and the valve activating times (Inlet pressure=brake circuit pressure).